Tiêu đề CM 2. EXO Notes version 2 Urine.pdf ✅

1 Clinical Microscopy – Urine | JBCRMT URINE  RENAL PHYSIOLOGY  The kidneys are bean shaped and are located on the posterior abdominal wall in the area known as the _______________  An adult human kidney has a mass of approximately 150 g and measures roughly 12.5 cm in length, 6 cm in width, and 2.5 cm in depth  Each kidney contains approximately functional units called nephrons  __________________ o makes up approximately 85% of the total nephron o Found mainly in the cortex of the kidney and are responsible primarily for ______________________________  __________________ o have loops of Henle that extend deep into the medulla of the kidney. o Their primary function is the ________________________.  GENERAL FUNCTIONS OF THE KIDNEY  Excretory Function  _______________________  _______________________  _______________________  _______________________ * Regulation of water balance in the body * Regulation of acid-base balance * Regulation of electrolytes * Regulation of Blood pressure through secretion of renin * Stimulates erythropoiesis through secretion of EPO  Renal Blood Flow  The renal artery supplies blood to the kidney  An ________________ at the vascular pole supplies blood individually to the glomerulus of each nephron.  The human kidney receives approximately ________________ of the blood pump  Total renal blood flow: _______________________  Renal plasma flow: _________________________ Order of Blood Flow in the Nephron: Order of Urine formation from the Nephron:  URINE FORMATION In the normal adult, approximately _______ of blood perfuses the kidneys each minute, which accounts for about ____ of the cardiac output.  GLOMERULAR FILTRATION  The glomerulus consists of a coil of approximately eight capillary lobes referred to collectively as the capillary tuft. It resembles as ______.  The glomerulus is located within the ______________.  A non-selective filter for plasma substances with molecular weights of less than _____________  Normally, the fluid leaving the glomerulus has a specific gravity of _____.  Analysis of the fluid as it leaves the glomerulus shows the filtrate to have a specific gravity of 1.010 and confirms that it is chemically an ultrafiltrate of plasma.
2 Clinical Microscopy – Urine | JBCRMT  Barrier’s that prohibits the filtration of large molecules: o The capillary wall of glomerulus is fenestrated o Intertwining foot processes – _______________ o ________________ - repels molecules with a negative charge even molecules are small enough to pass.  Glomerular Pressure o ____________________________ maintains the glomerular blood pressure o ___________________________ : Dilation of afferent arteriole, constriction of efferent arteriole o ___________________________ : Constriction of afferent arteriole, dilation of efferent arteriole  Renin-Angiotensin-Aldosterone System (RAAS) o System regulates the flow of blood to and within the glomerulus. The system responds to changes in blood pressure and plasma sodium content that are monitored by the juxtaglomerular apparatus, which consists of the ____________ in the afferent arteriole and the _____________ of the distal convoluted tubule o Actions:  Dilation of the afferent arteriole and constriction of the efferent arteriole  Stimulation of sodium reabsorption in the proximal convoluted tubule  Triggers the adrenal cortex to release the sodium-retaining hormone, aldosterone, to cause reabsorption of sodium and excretion of potassium in the distal convoluted tubule and collecting duct  Trigger release of antidiuretic hormone by the hypothalamus to stimulate water reabsorption in the collecting duct  TUBULAR REABSORPTION  The body must not lose 120mL of water-containing essential substances every minute.  The loss of tubular function is capability is often the first function affected in renal disease.  _________________________________  Two mechanisms of reabsorption: Substance Location ACTIVE TRANSPORT Movement of a substance across cell membranes into the bloodstream by electrichemicals energy Glucose, amino acids, salts PCT Chloride ALH Sodium PCT, DCT PASSIVE TRANSPORT Movement of a substance across a membrane by a diffusion because of a physical gradient Water PCT, DLH, CD Urea PCT, ALH Sodium ALH o _____________________: Denoted Tm, the maximal rate of reabsorption of a solute by the tubular epithelium per minute (milligrams per minute). Reabsorptive capacity varies with each solute and depends on the glomerular filtration rate o The plasma concentration at which active transport stops is termed the renal threshold  Glucose renal threshold is _____________ mg/dl or equivalent to 350mg/min
3 Clinical Microscopy – Urine | JBCRMT  Sodium renal threshold is 110 to 130 mmol/L  Renal Concentration o Renal concentration begins in the ___________________ and the final concentration of urine continues to the ___________ o Water is removed by osmosis in the descending loop of Henle, and sodium and chloride are reabsorbed in the ascending loop  ____________ o The movement of water across a semipermeable membrane in an attempt to achieve an osmotic equilibrium between two compartments or solutions of differing osmolality (i.e., an osmotic gradient). This mechanism is passive, that is, it requires no energy  ____________ o Has replaced specific gravity as the test to assess renal concentration o Specific gravity includes number and size of molecules o Osmolarity only includes number of small molecules; Na and Cl are both equal to a large urea molecule o Clinical unit of measure is the milliosmole (mOsm) *Excessive reabsorption of water as the filtrate passes through the highly concentrated medulla is prevented by the water-impermeable walls of the ascending loop. This selective reabsorption process is called the countercurrent mechanism and serves to maintain the osmotic gradient of the medulla  Effect of Anti- Diuretic Hormone on Renal Concentration o ADH- hormone responsible for reabsorption of ___________ in the distal convoluted tubules and collecting ducts of the kidney. o ↑ Body Hydration = ↓ADH = ↑ Urine Volume o ↓ Body Hydration = ↑ADH = ↓ Urine volume  RENAL SECRETION  Involves the passage of substances from the blood in the peritubular capillaries to the tubular filtrate  In contrast to tubular reabsorption, in which substances are removed from the glomerular filtrate and returned to the blood, tubular secretion involves the passage of substances from the blood in the peritubular capillaries to the tubular filtrate  Two major function of tubular secretion: o Elimination of waste products not filtered by the glomerulus o Regulation of acid-base balance in the body through the secretion of ____________________ * Along with the lungs, the kidneys are the major regulators of the acid–base content in the body. They do this through the secretion of hydrogen in the form of ammonium ions, hydrogen phosphate, and weak organic acids, and by the reabsorption of bicarbonate from the filtrate in the convoluted tubules.  RENAL FUNCTION TESTS  TESTS FOR GLOMERULAR FILTRATION  _________________________ - Best indicator of overall glomerular function o Inulin clearance test  _____________________  Inulin is a polymer of fructose, is an extremely stable substance that is not reabsorbed or secreted by the tubules. It is not a normal body constituent, however, and must be infused by IV at a constant rate throughout the testing period. o Creatinine clearance test  _____________________________  Creatinine is a waste product of muscle metabolism that is produced enzymatically by creatine phosphokinase from creatine, which links with ATP to produce ADP and energy  UV/P Urine (U) and Plasma (P) creatinine in mg/dL  UV/P x 1.73/A Urine Volume (V) in mL/min
4 Clinical Microscopy – Urine | JBCRMT  Disadvantages a. Some creatinine is secreted by the tubules, and secretion increases as blood levels rise b. Medications, including gentamicin, cephalosporins, and cimetidine (Tagamet), inhibit tubular secretion of creatinine, thus causing falsely low serum levels c. Bacteria will break down urinary creatinine if specimens are kept at room temperature for extended periods, thus leads to false low result d. A diet heavy in meat consumed during collection of a 24-hour urine specimen will influence the results if the plasma specimen is drawn before the collection period e. Not reliable indicator in athletes, persons involved in heavy exercise, and patients with muscle diseases f. Drugs such as trimethoprim-sulfamethoxazole can increase serum creatinine level by approximately 0.4 to 0.5 mg/dL g. Creatinine clearance is affected by sex and race. Women have less muscle mass and a lower rate of creatinine production in comparison to men o Cystatin C  A small protein (molecular weight 13,359) produced at a constant rate by all nucleated cells.  It is readily filtered by the glomerulus and reabsorbed and broken down by the renal tubular cells. It has potential as a marker for long-term monitoring of renal function  Its plasma concentration is inversely related to GFR.  The rate of production is not affected by muscle mass, sex, or race  Monitors pediatrics patients, diabetics, elderly and critically ill patients  Immunoassay procedures available o Beta 2 microglobulin  It dissociates from human leukocyte antigens (MHC class I) at a constant rate and is rapidly removed from the plasma by glomerular filtration.  It is a ________________________________________________than of glomerular function o Radioisotopes o Urea clearance test = _________________________  Estimated Glomerular Filtration Rate (eGFR) Computation o ______________________________________ – most frequently used formula o Original MDRD formula o Cockroft and Gault formula  TESTS FOR TUBULAR REABSORPTION  _________________________ – measures only the number of particles on solution o Major clinical uses of osmolarity include initially evaluating renal concentrating ability, monitoring the course of renal disease, monitoring fluid and electrolyte therapy, establishing the differential diagnosis of hypernatremia and hyponatremia, and evaluating the secretion of and renal response to ADH. o The normal urine to serum ratio should be ______________ o Measurement of freezing point depression was the first principle incorporated into clinical osmometers, and many instruments  By far the greatest source of error in any clearance procedure utilizing urine is the use of ______________________  Plasma/serum creatinine can be collected anytime within 24 hours of urine collection  A blood sample of 1 mL (minimum 0.5 mL) in a labeled tube, preferably stored in refrigerated or frozen temperature  A 24-hour urine sample is collected from the patient to measure creatinine clearance